Which of the following voltage range is used in medium transmission lines?

• A. 20 kV to 100 kV
• B. More than 200 kV
• C. 50 kV to 200 kV
• D. Less than 20 kV

Answer: (A)

Medium transmission line:- When the length of an overhead transmission line is between 100 km and 250 kin with an operating voltage ranging from 20 kV to 100 kV, it is considered as a medium transmission line.
In medium lines, the series impedance and shunt admittance (pure capacitance) lumped at a few pre-determined locations are considered for calculation. These lines can be analyzed by using load end capacitance, nominal-T, and nominal-π methods.
Short transmission line:- When the length of an overhead transmission line is less than 80 km with an operating voltage upto 20 kV, it is considered a short transmission line. Due to the smaller length and low operating voltage, the charging current is low. So, the effect of capacitance on the performance of short transmission lines is extremely small and therefore, can be neglected.
Long transmission line:- Lengths of more than 250 km are classified as long transmission lines; with an operating voltage of above 100 kV.